What is wrong with my hamster?

My hamster is a little over 2 years and the only one left of her litter. I can not tell if she has a tumor, wet tail or something else. She has been bleeding from her rectum along with some sort of drainage. She does not have diarrhea and is eating and drinking fine. I have noticed that there is a large bulge growing in her lower abdomen that seems to be getting bigger. What is wrong with her? help... please